Aqueous dental compositions such as one-part self-etching, self-priming dental adhesive compositions are known from the prior art and typically contain a mixture of an acid, a polymerizable monomer and an initiator system in a suitable aqueous solvent. Self-etching means that the dental adhesive composition may be applied to a tooth without any preliminarily etching of enamel and dentin in a separate method step. In order to provide a self-etching feature, the composition must be acidic. Self-priming means that the dental adhesive composition may be applied to a tooth without any preliminarily application of a primer.
The acidity of the mixture must be adapted to provide sufficient etching activity on dentin and enamel surfaces. However, an increased acidity leads to a complex stability problem due to the activation of chemical bonds of the functional components of the mixture. Specifically, ester bonds present in the polymerizable monomers may be solvolysed under acid catalysis.
As a result of the stability problem of the mixture, the storage stability at room temperature of commercial one-part self-etching, self-priming dental adhesive compositions known from the prior art may be insufficient. Typical commercial one-part self-etching, self-priming dental adhesive compositions must be stored in a refrigerator in order to avoid deterioration by solvolysis or polymerization.
WO03/013444 discloses a one-part self-priming dental adhesive. WO03/013444 does not relate to dental adhesive compositions containing a polymerizable acidic phosphoric acid ester monomer.
WO98/57612 discloses composite materials and adhesion promoters. WO98/57612 does not relate to dental adhesive compositions containing polymerizable N-substituted alkyl acrylic or acrylic acid amide monomers.
WO00/30591 discloses self etching adhesive dental primer compositions and polymerizable surfactants. WO00/3059 does not relate to dental adhesive compositions containing polymerizable N-substituted alkyl acrylic or acrylic acid amide monomers.
WO00/10478 discloses adhesive compositions containing pentaerythritol triallyl ether monophosphate acid ester (PTEPAE). However, the compositions do not represent aqueous mixture and do not contain polymerizable sulfonic acid esters or polymerizable N-substituted alkyl acrylic or acrylic acid amide monomers or an organic water-miscible solvent and/or water. The compositions of WO00/10478 cannot be used as one-part self-etching, self-priming dental adhesive composition because the compositions are not aqueous mixtures. Moreover, hydrolysis stability cannot be provided by the compositions according to WO00/10478 because HEMA is always present in the compositions.
EP-A 1 548 021 discloses a one-part self-etching, self-priming dental adhesive composition having a pH of at most 2, which comprises a polymerizable acidic phosphoric acid ester monomer. However, the specific polymerizable acidic phosphoric acid ester monomers are neither disclosed nor suggested in this reference.
It is the problem of the present invention to provide an aqueous dental composition, in particular a one-part self-etching, self-priming dental adhesive composition, having a high storage stability and an excellent adhesion both to dentin and enamel.